Search Help

The search engine has four modes of operation. The first three of these are the easiest to use. with the fourth provides advanced options that can be used to refine your query.

1. Return documents that contain any of the words

   This option will return all the pages in the index that contain any one of the words you enter. For example, if you type foo bar in the search box, the search engine will return documents containing the word 'foo', documents containig the word 'bar', and documents containing both the words.

2. Return documents that contain all of the words

   This option will only return pages that contain every word you typed in the search box. For the same query as above, only documents containing both the words 'foo' and 'bar' would be returned; documents containing only one of the words would not.

3. Return documents that contain the exact phrase

   This option will only return documents that contain exactly what you typed, character for character, in the search box. Again for our query foo bar, only documents containing 'foo' and 'bar', in that order and with no words between them, would be returned

4. Return documents that match the boolean expression

   Here you can specify, using a boolean expression, what documents to return. You can use operators to link search terms, build compound expressions, and group expressions using brackets. Here is a list of the operators and examples of how they are used:

   • AND: The query hardware AND software will return documents that contain both the words 'hardware' and 'software'
   • OR: The query windows OR linux will return documents that contain either the words 'windows' or 'linux', and the documents that contain both words
   • NOT: NOT computers will show all paged that do not contain the word 'computers'
   • XOR: This operator means 'exclusive or', and is similar to the OR operator, but does not return pages that contain both of the search terms. perl XOR java will return documents that contain the words 'perl' or 'java', but will not return documents containing both of these words
   • NEAR: This operator works like AND, but in addition to the document having to contain both of the search terms, they must also be within 50 characters of each other. Note that you cannot supply a compound expression to the NEAR operator; the query CGI NEAR (programs OR scripts) is invalid, use (CGI NEAR programs) OR (CGI NEAR scripts) instead.
   • The operators NAND, NOR and XNOR are negated versions of the AND, OR and XOR operators. For example, NOT (foo OR bar) is the same as foo NOR bar
   If you want to use more than one word as a search term for an operator, you must enclose the words in double quotes, or you will produce an invalid boolean expression, for example foo AND "bar baz"